5.2. Accessibility

Some users may need specific support because of e.g. some visual
impairment.
USB braille displays are detected
automatically, but most other
accessibility features have to be enabled manually.
Some boot parameters can be appended to
enable accessibility features.
Note that on most architectures the boot loader interprets your keyboard as
a QWERTY keyboard.

5.2.1. USB Braille Displays

USB braille displays should be automatically detected. A textual version
of the installer will then be automatically selected, and support for the
braille display will be automatically installed on the target system.
You can thus just press Enter at the boot menu.
Once brltty is started, you can choose a braille
table by entering the preference menu. Documentation on key
bindings for braille devices is available on the brltty website.

5.2.2. Serial Braille Displays

Serial braille displays cannot safely be automatically detected
(since that may damage some of them). You thus need to append the
brltty=driver,port,table
boot parameter to tell brltty which driver it
should use. driver should be replaced by the
two-letter driver code for your terminal (see the
driver code list).
port should be replaced by the name of the
serial port the display is connected to, ttyS0 is
the default. table is the name of the braille
table to be used (see the table code
list); the English table is the default. Note that the table can
be changed later by entering the preference menu. Documentation on key
bindings for braille devices is available on the brltty website.

5.2.3. Board Devices

Some accessibility devices are actual boards that are plugged inside the
machine and that read text directly from the video memory. To get them
to work framebuffer support must be disabled by using the
fb=false
boot parameter. This will however reduce the number of available languages.

5.2.4. High-Contrast Theme

For users with low vision, the installer can use a high-contrast
theme that makes it more readable. To enable it, append the
theme=dark boot parameter.